The main risk to beer is from bacteria. Fortunately, beer is a poor and hostile environment for most microorganisms. This is because the ethanol concentration and low pH is below what most bacteria can tolerate for growth. However, if the wrong bacteria are present and have colonized the brew, then a bitter frothy drink can be transformed into a sour tasting, cloudy, off-color, undrinkable beverage.
It is to guard against this that beer, along with other liquids at risk from food-spoilage microbes, is tested throughout the production process. Beer spoilage organisms are either lactic acid bacteria, such as the sort used to make yoghurt, or they are anaerobic bacteria, associated with bad odors.
One problem is that standard laboratory methods require long incubation times in order to produce a meaningful result. These classic methods require a sample of the beer to be filtered through a membrane. The membrane has pores which allow the liquid to pass through, but which are small enough to capture bacteria. The membrane is placed onto agar and the microorganisms allowed to grow, under a defined temperature, for a period of time. This means that the brewer will only know the status of a batch of beer a considerable time after a contamination event occurred.
In a breakthrough in the realm of rapid microbiological methods, scientists based at GEN-IAL from Troisdorf and Fraunhofer Institute for Applied Polymer Research IAP in Potsdam, have jointly created a polymer powder that reduces the time to result down to two days.
With the method, the powder is added to a small sample of beer. The polymer is designed to binds to the surface of the bacteria. If pathogens are present, these can later be removed along with the particles for analysis.
The new compound has yet to be reported to a science journal. Development work is continuing and the researchers are working towards a commercial kit.
